chromium/third_party/blink/web_tests/external/wpt/css/css-anchor-position/position-try-container-query.html

<!DOCTYPE html>
<title>@position-try with container query responding to fallback widths</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/#fallback">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
  #relative {
    background: maroon;
    position: relative;
    width: 195px;
    height: 200px;
  }
  #target1 {
    container-type: inline-size;
    container-name: target1;
    position-try-fallbacks: --fallback1;
    background: green;
    position: absolute;
    top: 0px;
    left: 999999px; /* force fallback */
    width: 100px;
    height: 100px;
  }
  @position-try --fallback1 {
    top: 100px;
    left: 0px;
    width: 150px;
  }
  @container (width > 100px) {
    #inner1 {
      background-color: lime;
      width: 100px;
      height: 100px;
    }
  }

  #target2 {
    container-type: inline-size;
    container-name: target2;
    position-try-fallbacks: --fallback2, --fallback3;
    background: orange;
    position: absolute;
    top: 0px;
    left: 999999px; /* force fallback */
    width: 100px;
  }
  @position-try --fallback2 {
    top: 100px;
    left: 0px;
    width: 150px;
  }
  @position-try --fallback3 {
    top: 0px;
    left: 0px;
    width: 150px;
  }
  @container target2 (width = 150px) {
    #inner2 {
      background-color: yellow;
      width: 100px;
      height: 150px;
    }
  }
</style>
<div id="relative">
  <div id="target1">
    <div id="inner1"></div>
  </div>
  <div id="target2">
    <div id="inner2"></div>
  </div>
</div>
<script>
  test(() => {
    assert_equals(getComputedStyle(inner1).backgroundColor, "rgb(0, 255, 0)");
    assert_equals(getComputedStyle(inner1).width, "100px");
    assert_equals(getComputedStyle(inner1).height, "100px");
    assert_equals(getComputedStyle(target1).top, "100px");
    assert_equals(getComputedStyle(target1).left, "0px");
    assert_equals(getComputedStyle(target1).width, "150px");
  }, "Size container query responds to fallback width");

  test(() => {
    assert_equals(getComputedStyle(inner2).backgroundColor, "rgb(255, 255, 0)");
    assert_equals(getComputedStyle(inner2).width, "100px");
    assert_equals(getComputedStyle(inner2).height, "150px");
    assert_equals(getComputedStyle(target2).top, "0px");
    assert_equals(getComputedStyle(target2).left, "0px");
    assert_equals(getComputedStyle(target2).width, "150px");
  }, "Size container query responds to fallback width and applies height to not fit the first fallback");
</script>